Resonance dampening actuator bearing assembly

Abstract

An improved pivot mechanism for a disc drive actuator assembly, the actuator assembly having an E-block which supports an array of read/write heads in reading and writing data relationship to a plurality of data discs, the actuator assembly having a bearing cartridge that rotatably supports the E-block and is receivingly disposed within a bore of the E-block and fixed therein by a tolerance ring interposed in the bore between the bearing cartridge and the E-block. The bearing cartridge has a hollow sleeve that supports the tolerance ring on an outer diameter thereof, and furthermore supports a damping member on the inner diameter thereof. The damping member is attached to the sleeve by a selected damping material.

What is claimed is: 
     
       1. An actuator for a disc drive, comprising: an E-block forming a central supporting body;   a bore centrally displaced within the E-block;   a plurality of arms supported by the E-block;   an array of read/write heads supported by the arms;   a coil supported by the E-block;   a bearing cartridge disposed in the bore of the E-block, the bearing cartridge comprising: a stationary shaft;   a bearing supported by the shaft;   a circular sleeve encasing the stationary shaft and rotatably supported by the bearing for rotation about the stationary shaft; and   a circular damping member circumferentially supported by an inner surface of the sleeve and encased within the circular sleeve and encasing the shaft for damping resonant frequencies of the E-block; and     a tolerance ring interposed between the bearing cartridge and the E-block to secure the bearing cartridge within the bore.   
     
     
       2. The actuator of claim 1 wherein the circular sleeve comprises a groove for circumferentially housing the tolerance ring. 
     
     
       3. The actuator of claim 2 wherein the tolerance ring has an inner surface pressingly engaging the groove, and an outer surface engaging the bore surface, the inner surface and outer surface forming a plurality of projecting corrugations. 
     
     
       4. The actuator of claim 3 wherein the damping member is attached to the sleeve by a circular damping material comprising a viscoelastic polymer. 
     
     
       5. The actuator of claim 4 wherein the viscoelastic polymer comprises ethylene acrylic. 
     
     
       6. The actuator of claim 5 wherein the damping member comprises tungsten alloy. 
     
     
       7. The actuator of claim 4 wherein the damping material is injected between the damping member and the sleeve. 
     
     
       8. The actuator of claim 4 wherein the damping material is formed of a sleeve of material interposed between the damping member and the sleeve. 
     
     
       9. In a disc drive assembly having a base deck, a spindle motor supported by the base deck, a disc connected to the spindle motor for rotation and having a data surface, and a cover which cooperates with the base deck to provide a sealed enclosure, an actuator assembly comprising: an E-Block having a bore;   a bearing cartridge supported by the base deck and cover; the bearing cartridge comprising: a stationary shaft;   a bearing supported by the shaft;   a circular sleeve encasing the stationary shaft and rotatably supported by the bearing for rotation about the stationary shaft; and   a circular damping member circumferentially supported by the sleeve for damping resonant frequencies of the E-block; and     a tolerance ring interposed between the bearing cartridge and the E-block to secure the bearing cartridge within the bore.   
     
     
       10. The apparatus of claim 9 wherein the circular sleeve comprises a groove for circumferentially housing the tolerance ring. 
     
     
       11. The apparatus of claim 10 wherein the tolerance ring has an inner surface pressingly engaging the groove, and an outer surface engaging the bore surface, the inner surface and the outer surface forming a plurality of projecting corrugations engaging the bore surface. 
     
     
       12. The apparatus of claim 11 wherein the damping member is attached to the sleeve by a circular damping material comprising a viscoelastic polymer. 
     
     
       13. The apparatus of claim 12 wherein the viscoelastic polymer is ethylene acrylic. 
     
     
       14. The apparatus of claim 13 wherein the damping member comprises tungsten alloy. 
     
     
       15. The actuator of claim 12 wherein the damping material is injected between the damping member and the sleeve. 
     
     
       16. The actuator of claim 12 wherein the damping material is formed of a sleeve of material interposed between the damping member and the sleeve.